1. Field of the Invention
The present invention relates to an RFID (Radio Frequency Identification) thread which transmits information such as ID (Identification) recorded in an IC chip through RF (Radio Frequency), a sheet with the RFID thread, and a printing machine for the sheet with the RFID thread.
2. Description of Relevant Art
With the progress of copying technology, since a fine copy is easily obtained, there is no end of events to illegally copy and use a bill and a security pass. For preventing these illegal acts, a watermark (black watermark) has been used for a bill. In addition, a medium which is required for easy verification of authenticity, for example, a bill, security pass, show ticket, and ID card in recent years is likely to be provided with an action, for example, for putting a hologram seal thereon or skimming a thread therein. Further, as a high-tech anticounterfeit technology, for example, a semiconductor chip is fixed on these forms or embedded in the papers.
An anticounterfeit thread with an IC chip has been developed, in which a metal evaporated film is formed on one side of a polyester film and a semiconductor chip with an external antenna mounted on the chip is pasted on the upper side of the film (see Japanese Patent Laid-Open Publication No. 2004-139405, FIG. 2). In the thread, a marker is formed between the IC chips and positions of the IC chips can be identified. In addition, when a paper containing a thread is manufactured, since the thread is stretched due to a tensile force applied thereon when the thread is inserted into the paper, a position of the IC chip on the thread is controlled by controlling the tensile force to be applied on the thread.
According to the technology described in the Japanese Patent Laid-Open Publication No. 2004-139405, a thread on which an IC chip is mounted on a medium such as a paper is mounted. However, a papermaking machine is operated at high speed, and a paper skimming speed ranges from 200 m/minute to 1500 m/minute at higher speed. In the papermaking machine being operated at such a high speed, it is not easy to control a tensile force of the thread for controlling a position of the IC chip. Since a paper is skimmed at high speed, it is easy to think that a small displacement of a position of the IC chip causes a large displacement of the position after a few seconds. In addition, a paper in which a position of the IC chip is displaced becomes a defective paper since information of the IC chip can not be read, and the paper is recycled. Accordingly, the environmental load and cost are increased.
The present invention has been developed considering the problems described above, and it is an object of the present invention to provide an RFID thread which can be easily mounted on a sheet without precisely controlling a mounting position of an IC chip when the RFID thread is mounted on the sheet such as a paper, the sheet with the RFID thread, and a printing machine for the sheet with the RFID thread.